International Journal of
MediPharm Research

Two titrimetric and one spectrophotometric methods are described for the determination of diethylcarbamazine citrate in bulk drug and dosage forms using permanganate as an oxidimetric agent. In method A,the drug solution in H2SO4 is titrated directly at 800C to pink end point. DEC was treated with a measured excess of standard permanganate in H2SO4 medium, and after a contact time of 5 min, the residual oxidant back titrated with ammonium ferrous sulphate to a colorless end point (method B). Spectrophotometry is based on the measurement of the unreacted permanganate at 545 nm after the reaction between DEC and permanganate in H2SO4 medium is ensured to be complete (method C). In all methods, the amount of permanganate reacted was related to the amount/concentration of DEC. Experimental variables associated with the assay were carefully examined and optimized for better performance characteristics. Both the titrimetric methods are applicable for 1-10 mg range and the reaction follows 1:3 and 1:4 (DEC:KMnO4) stoichiometry in direct and indirect methods, respectively. In spectrophotometry, Beer's law is obeyed in the inverse manner, and linearity is observed in the range 2.5-30 µg mL-1 with a molar absorptivity value of 8.03×103L mol-1 cm-1. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.12 and 0.35 µg mL-1, respectively. The methods were validated for precision and accuracy, robustness and ruggedness and selectivity. The methods were applied to the determination of DEC in tablets and syrup with satisfactory results. The accuracy of the methods was also assessed by recovery study via standard-addition procedure. Keywords : Diethylcarbamazine citrate; assay; titrimetry; spectrophotometry; permanganate; pharmaceuticals..